Nasir al-Din al-Tusi's Memoir on Astronomy (al-Tadhkira fi cilm al-hay'a)

I was introduced to Tiisi: and his Tadhkira some 19 years ago. That first meeting was neither happy nor auspicious. My graduate student notes from the time indicate a certain level of confusion and frustration; I seem to have had trouble with such words as tadwlr (epicycle), which was not to be found in my standard dictionary, and with the concept of solid-sphere astronomy, which, when found, was ...